CS310 Quantum Sensor
Full Spectrum
An accurate, stable, and durable PAR measurement under all light sources
weather applications water applications energy applications gas flux & turbulence applications infrastructure applications soil applications


The CS310 is a self-powered, analog full-spectrum quantum sensor with a 0 to 40 mV output. The sensor incorporates a blue-enhanced silicon photodiode and custom optical filters with a rugged, self-cleaning sensor housing design that includes an anodized aluminum body with an acrylic diffuser. Typical applications include PPFD measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, as well as reflected or under-canopy (transmitted) PPFD measurement in the same environments.

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Benefits and Features

  • Full-spectrum quantum sensor with a spectral range of 389 to 692 nm (±5 nm)
  • Accurate measurements under all light sources including Light Emitting Diodes (LEDs)
  • Dome-shaped anodized aluminum body designed to be rugged and self-cleaning for a longer life and lower maintenance
  • IP68 rating for submersion in water up to depths of 30 m; suitable for aquatic applications or an extra assurance in harsh environments
  • Sensor head detachable from the cable with a waterproof stainless-steel connector for fast, easy servicing
  • Factory calibration data stored in the sensor so no sensor-specific calibration coefficients required for an accurate measurement
  • Each sensor carefully calibrated in controlled conditions and traceable to NIST reference standards
  • Four-year manufacturer warranty


CS310 glam view
CS310 glam view
CS310 glam view
CS310 front view
CS310 back view
CS310 left view
CS310 right view
CS310 top view
CS310 bottom view
CS310 with 5 m cable
CS310 with cable mounted to a leveling base and connected to another cable (sold separately)
CS310 mounted to a leveling base, bracket, and pole (sold separately)
Mean spectral response measurements of six replicate Apogee SQ100 and CS310 quantum sensors

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Detailed Description

Radiation that drives photosynthesis is called photosynthetically active radiation (PAR) and is typically defined as total radiation across a range of 400 to 700 nm. PAR is often expressed as photosynthetic photon flux density (PPFD): photon flux in units of micromoles per square meter per second (µmol m-2 s-1, equal to microEinsteins per square meter per second) summed from 400 to 700 nm (total number of photons from 400 to 700 nm). While Einsteins and micromoles are equal (one Einstein = one mole of photons), the Einstein is not an SI unit, so expressing PPFD as µmol m-2 s-1 is preferred.

Sensors that measure PPFD are often called quantum sensors due to the quantized nature of radiation. A quantum refers to the minimum quantity of radiation (one photon) involved in physical interactions (for example, absorption by photosynthetic pigments). In other words, one photon is a single quantum of radiation.

Typical applications of quantum sensors include incoming PPFD measurement over plant canopies in outdoor environments or in greenhouses and growth chambers, and reflected or under-canopy (transmitted) PPFD measurement in the same environments.

The CS310 quantum sensor consists of a cast acrylic diffuser (filter), photodiode, and signal processing circuitry mounted in an anodized aluminum housing with a cable to connect the sensor to a measurement device. The CS310 quantum sensor is designed for continuous PPFD measurement in indoor or outdoor environments. It outputs an analog signal that is directly proportional to PPFD. The analog signal from the sensor is directly proportional to radiation incident on a planar surface (does not have to be horizontal), where the radiation emanates from all angles of a hemisphere.


  • Federer, C.A., and C.B. Tanner, 1966. Sensors for measuring light available for photosynthesis. Ecology 47:654-657.
  • Ross, J., and M. Sulev, 2000. Sources of errors in measurements of PAR. Agricultural and Forest Meteorology 100:103-125.
  • Federer, C.A., and C.B. Tanner, 1966. Sensors for measuring light available for photosynthesis. Ecology 47:654-657.
  • Inada, K., 1976. Action spectra for photosynthesis in higher plants. Plant and Cell Physiology 17:355-365.
  • McCree, K.J., 1972a. The action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agricultural Meteorology 9:191-216.
  • McCree, K.J., 1972b. Test of current definitions of photosynthetically active radiation against leaf photosynthesis data. Agricultural Meteorology 10:443-453.
  • Sager, J.C., W.O. Smith, J.L. Edwards, and K.L. Cyr, 1988. Photosynthetic efficiency and phytochrome photoequilibria determination using spectral data. Transactions of the ASAE 31:1882-1889.

Spectral Response

Refer to the mean spectral response graph in the Images section of the web page. The graph shows the mean spectral response measurements of six replicate Apogee SQ100 and CS310 quantum sensors. Spectral response measurements were made at 10 nm increments across a wavelength range of 300 to 800 nm in a monochromator with an attached electric light source. Measured spectral data from each quantum sensor were normalized by the measured spectral response of the monochromator/electric light combination, which was measured with a spectroradiometer.


Power Supply Self-powered
Output (Sensitivity) 0.01 mV per µmol m-2 s-1
Calibration Factor (Reciprocal of Sensitivity) 100.0 µmol m-2 s-1 per mV
Calibration Uncertainty ±5% (for daily total radiation)
Calibrated Output Range 0 to 40 mV
Measurement Range 0 to 4000 µmol m-2 s-1
Measurement Repeatability < 1% (up to 4000 μmol m-2 s-1)
Long-Term Drift < 2% per year
Non-Linearity < 1% (up to 4000 µmol m-2 s-1)
Response Time < 1 ms
Field of View (FOV) 180°
Spectral Range 389 to 692 nm ±5 nm (wavelengths where response is greater than 50% of maximum)
Spectral Selectivity < 10% from 412 to 682 nm ±5 nm
Directional (Cosine) Response ±5% (at 75° zenith angle)
Azimuth Error < 0.5%
Tilt Error < 0.5%
Temperature Response -0.11 ±0.04% per °C
Uncertainty in Daily Total < 5%
Detector Blue-enhanced silicon photodiode
Housing Anodized aluminum body with acrylic diffuser
IP Rating IP68
Operating Environment -40° to +70°C (0 to 100% relative humidity; can be submerged in water up to depths of 30 m)
Cable 5 m of shielded, twisted-pair wire

Additional cable available in multiples of 5 m; Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions); pigtail lead wires
Warranty 4 years (against defects in materials and workmanship)
Diameter 2.4 cm (0.9 in.)
Height 3.5 cm (1.4 in.)
Weight 100 g with 5 m of lead wire (3.53 oz with 16.4 ft of lead wire)


Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.


Product Compatible Note
21X (retired)
CR10 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR9000 (retired)

Additional Compatibility Information


Accurate measurements require the sensor to be leveled using a 18356 leveling fixture. This leveling fixture incorporates a bubble level and three leveling screws. The 18356 mounts to a crossarm using the CM225 mounting stand or 015ARM. The CS310 should be mounted away from all obstructions and reflective surfaces that might adversely affect the measurement.

Frequently Asked Questions

Number of FAQs related to CS310: 3

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  1. The leveling base provides physical stability and helps ensure the sensor is leveled correctly. It is not recommended to use the sensor without the base. The sensor mounts to the base with an included bolt. However, a user-supplied plate with a hole drilled in it could be used instead to accept the sensor’s mounting bolt.

  2. The Clear Sky Calculator (www.clearskycalculator.com) can be used to determine the need for quantum sensor recalibration. It determines PPFD incident on a horizontal surface at any time of day at any location in the world. It is most accurate when used near solar noon in spring and summer months, where accuracy over multiple clear and unpolluted days is estimated to be ±4% in all climates and locations around the world. For best accuracy, the sky must be completely clear, as reflected radiation from clouds causes incoming radiation to increase above the value predicted by the clear sky calculator. Measured values of PPFD can exceed values predicted by the Clear Sky Calculator due to reflection from the sides and edges of clouds. This reflection increases the incoming radiation. The influence of high clouds typically shows up as spikes above clear sky values, not a constant offset greater than clear sky values.

    To determine recalibration need, input site conditions into the calculator and compare PPFD measurements to calculated PPFD values for a clear sky. If sensor PPFD measurements over multiple days near solar noon are consistently different than calculated values (by more than 6%), the sensor should be cleaned and re-leveled. If PPFD measurements are still different after a second test, contact Campbell Scientific for an RMA to get the sensor recalibrated.

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